A bad job is the one triggered TDR(In the current amdgpu's
implementation, actually all the jobs in the current joq-queue will
be treated as bad jobs). In the recovery process, its fence
will be fake signaled and as a result, the work behind will be scheduled
to delete it from the mirror list, but if the TDR process is invoked
before the work's execution, then this bad job might be processed again
and the call dma_fence_set_error to its fence in TDR process will lead to
kernel warning trace:

[  143.033605] WARNING: CPU: 2 PID: 53 at ./include/linux/dma-fence.h:437 amddrm_sched_job_recovery+0x1af/0x1c0 [amd_sched]
kernel: [  143.033606] Modules linked in: amdgpu(OE) amdchash(OE) amdttm(OE) amd_sched(OE) amdkcl(OE) amd_iommu_v2 drm_kms_helper drm i2c_algo_bit fb_sys_fops syscopyarea sysfillrect sysimgblt kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 snd_hda_codec_generic crypto_simd glue_helper cryptd snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq joydev snd_seq_device snd_timer snd soundcore binfmt_misc input_leds mac_hid serio_raw nfsd auth_rpcgss nfs_acl lockd grace sunrpc sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 8139too floppy psmouse 8139cp mii i2c_piix4 pata_acpi
[  143.033649] CPU: 2 PID: 53 Comm: kworker/2:1 Tainted: G           OE    4.15.0-20-generic #21-Ubuntu
[  143.033650] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[  143.033653] Workqueue: events drm_sched_job_timedout [amd_sched]
[  143.033656] RIP: 0010:amddrm_sched_job_recovery+0x1af/0x1c0 [amd_sched]
[  143.033657] RSP: 0018:ffffa9f880fe7d48 EFLAGS: 00010202
[  143.033659] RAX: 0000000000000007 RBX: ffff9b98f2b24c00 RCX: ffff9b98efef4f08
[  143.033660] RDX: ffff9b98f2b27400 RSI: ffff9b98f2b24c50 RDI: ffff9b98efef4f18
[  143.033660] RBP: ffffa9f880fe7d98 R08: 0000000000000001 R09: 00000000000002b6
[  143.033661] R10: 0000000000000000 R11: 0000000000000000 R12: ffff9b98efef3430
[  143.033662] R13: ffff9b98efef4d80 R14: ffff9b98efef4e98 R15: ffff9b98eaf91c00
[  143.033663] FS:  0000000000000000(0000) GS:ffff9b98ffd00000(0000) knlGS:0000000000000000
[  143.033664] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  143.033665] CR2: 00007fc49c96d470 CR3: 000000001400a005 CR4: 00000000003606e0
[  143.033669] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  143.033669] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  143.033670] Call Trace:
[  143.033744]  amdgpu_device_gpu_recover+0x144/0x820 [amdgpu]
[  143.033788]  amdgpu_job_timedout+0x9b/0xa0 [amdgpu]
[  143.033791]  drm_sched_job_timedout+0xcc/0x150 [amd_sched]
[  143.033795]  process_one_work+0x1de/0x410
[  143.033797]  worker_thread+0x32/0x410
[  143.033799]  kthread+0x121/0x140
[  143.033801]  ? process_one_work+0x410/0x410
[  143.033803]  ? kthread_create_worker_on_cpu+0x70/0x70
[  143.033806]  ret_from_fork+0x35/0x40

So just delete the bad job from mirror list directly

Changes in v3:
	- Add a helper function to delete the bad jobs from mirror list and call
		it directly *before* the job's fence is signaled

Changes in v2:
	- delete the useless list node check
	- also delete bad jobs in drm_sched_main because:
		kthread_unpark(ring->sched.thread) will be invoked very early before
		amdgpu_device_gpu_recover's return, then drm_sched_main will have
		chance to pick up a new job from the job queue. This new job will be
		added into the mirror list and processed by amdgpu_job_run, but may
		not be deleted from the mirror list on time due to the same reason.
		And finally re-processed by drm_sched_job_recovery
Signed-off-by: Trigger Huang <Trigger.Huang@amd.com>
Reviewed-by: Christian König <chrstian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>